The present invention relates generally to pharmacologically active pyridazinones and, more particularly, to certain novel antihypertensively effective substituted pyridazin(2H)-3-one compounds.
Substituted pyridazinone compounds having various substituents thereon have heretofore been prepared and proposed for use in a wide range of different ultimate applications.
For example, U.S. Pat. No. 3,689,652 discloses 6-(substituted phenyl)-4,5-dihydro-3(2H)-pyridazinones as hypotensive agents. More specifically, 6-halomethylphenyl-5-methyl (or unsubstituted)-4,5-dihydro-3(2H)-pyridazinone compounds are disclosed. In related U.S. Pat. Nos. 3,746,712, 3,812,256, 3,822,260, 3,876,786 and 3,876,787, the patentees further disclose corresponding 6-substituted phenyl-4,5-dihydro-pyridazinone compounds wherein the additional phenyl substituents include lower alkanoyl, nitro, amino, lower alkanoylamino and cyano wherein the 2- position of the pyridazinone ring may be optionally substituted by lower alkyl.
U.S. Pat. No. 3,657,242 discloses a series of 4,5-dihydro-pyridazin(2H)-3-one and hexahydropyridazines and, more specifically, certain 2-hydroxyalkyl-6-aryl or heterocyclic substituted-4,5-dihydro-pyridazinones and hexahydropyridazines useful as antiinflammatories.
In U.S. Pat. No. 3,931,177, the patentees disclose a series of 6-(3-substituted amino-2-hydroxy propoxyaryl)-4,5-dihydro-3(2H)-pyridazinones active as .beta.-adrenergic-blocking agents and antihypertensives.
The patentees in U.S. Pat. No. 3,975,388 disclose 6-alkoxy-, alkyl-, hydroxymethyl-, cycloalkylamino-, alkylamino- and heterocyclic-substituted phenyl-4,5-dihydro-3(2H)-pyridazinone compounds having antihypertensive activity.
The foregoing compounds are representative of 4,5-dihydro-pyridazinone compounds previously suggested as pharmacologically active compounds. As a chemical class, the foregoing compounds comprise dihydro (saturated) ketopyridazines.
Representative of another class of related compounds are the pyridaz-3-one compounds disclosed in U.S. Pat. No. 2,839,532. The aforesaid patent is directed to 4,5-unsaturated pyridaz-3-one (or 3-ketopyridazine) compounds having a cyano, acetyl, carboxyl, carboethoxy or benzoyl group in the 4- position optionally substituted in 5,6-positions by lower alkyl, phenyl or substituted phenyl residues. These compounds are disclosed as being useful as medicaments, particularly, analgesics, anesthetics, antibacterials or disinfectants.
U.S. Pat. No. 3,491,096 and British Pat. No. 840,522 are directed to other previously investigated pyridazone compounds. The aforementioned British patent pertains to 2-hydroxymethyl-6-phenyl-3-pyridazone and the analgesic utility thereof. U.S. Pat. No. 3,491,096 describes 2-pyridylalkylated-6-phenyl-pyridaz-3-one compounds possessing sedative, analgesic and antispasmodic properties, with occasional hypotensive effects being observed.